1. Field of the Invention
The present invention relates to a semiconductor device manufacturing method and a substrate processing apparatus for a semiconductor manufacturing process in which a ruthenium (Ru) film, a ruthenium oxide (RuO2) film, or a lamination film thereof is formed on the surface of a wafer.
2. Description of the Related Art
As for the formation of an Ru film and an RuO2 film which are candidates for capacitor electrodes of next-generation DRAMs, a film formation technique using sputtering has been established and is used widely on a research level. However, since this method is low in step coverage, a thermal CVD method is desired to be used for mass production because of its superior step coverage and research and development for that purpose are now being made enthusiastically. In the thermal CVD method, in general, the film forming material is in the form of a solution obtained by dissolving a liquid or a powder of an organic metal in a solvent; it is vaporized with a vaporizer or by bubbling and supplied onto a substrate. When an Ru film or an RuO2 film is formed on a substrate by a thermal CVD method, Ru films or RuO2 films are also deposited on members such as a substrate holder around the substrate in the processing chamber. As the film formation is performed repeatedly, Ru films or RuO2 films deposited on such members maypeel off to cause particles on a substrate, which is a factor in lowering the yield of device manufacture. Furthermore, if particles occur, it is necessary to stop operation of a manufacturing apparatus and to replace film-deposited members with new ones or perform wet cleaning. This lowers the working rate of the apparatus, that is, the mass-productivity.
One countermeasure against the above problem is to remove deposited films by cleaning the inside of the processing chamber. Example methods for cleaning Ru films or RuO2 films deposited in a processing chamber are a dry cleaning method and a wet cleaning method. One known dry cleaning method is a method using a ClF3 gas (refer to JP-A-2002-180250, for example).
However, conventional methods have a problem that the apparatus downtime due to cleaning is long and hence the productivity is low. Factors in causing a long downtime are a long cleaning time and generation of particles after cleaning.